WHAT'S UP DOC? Meningitis

Q: I thought no one in the U.S. got meningitis anymore, so why did my daughter’s pediatrician recommend the meningitis vaccination before she goes to college?

A: The meninges are the membranes that cover the brain and the spinal cord; inflammation of these is called meningitis. The most common cause of meningitis is infection. This can be caused by bacteria (the cause with the highest mortality), viruses (the most common cause, about ten times more common than bacterial meningitis), fungal infections or parasites. With over 4000 cases of bacterial meningitis (over 1 per 100,000 people, decreased from 2 per 100,000 since 1998 at least in part because of vaccinations) and over 500 deaths per year, this is still an important cause of morbidity and mortality. Non-infectious causes of meningitis include certain cancers, toxic reactions to chemicals, autoimmune conditions and others.

Risk factors for meningitis include extremes of age (very young or very old), immune compromise (including lack of a normally functioning spleen), and/or living in a community setting with close contacts with other people who may be carriers of one of the infectious agents (for example college students are at an increased risk).

The symptoms of meningitis include the triad of fever, headache and a stiff neck (often manifesting as pain when the patient tries to touch their chin to their chest), although not all patients will have all three. Other symptoms include nausea/vomiting, altered mental status, seizures, skin rash (specifically with certain types of infection), and others. Symptoms in newborns may include fever, irritability/excessive crying, poor feeding, excessive sleepiness/inactivity, and/or bulging of the fontanelle (the soft spot where the newborn’s skull has not completely formed).

Since meningitis is an inflammation of the meninges, a lumbar puncture (LP, also called a spinal tap, done by inserting a needle into the spinal canal by the lower back) is indicated to obtain a sample of the cerebral spinal fluid (CSF, a clear body fluid that surrounds and helps cushion the brain and spinal cord) so it can be evaluated for inflammatory cells, cultured (to look for bacteria) and sent for other specialized tests. Other tests include blood tests (especially blood cultures, as bacterial causes of meningitis may be from infection elsewhere in the body which travels through the blood to seed the meninges) and other tests. A CT scan may be done to look for signs of brain swelling (from extreme inflammation), and in some cases (in patient who are immunosuppressed, have a history of central nervous system disease, have had a new onset seizure within the last week, have an abnormal level of consciousness or have symptoms like those of an acute stroke) should be done before obtaining an LP, although antibiotic treatment for suspected cases of bacterial meningitis should be initiated immediately.

When acute meningitis is caused by certain types of bacteria the symptoms often develop rapidly, usually over 24 hours or less. The most common types of bacteria that cause acute meningitis include Group B strep, listeria, E. coli (these three are more likely in newborns as they may colonize mom’s vaginal mucosa and hence be transmitted to the baby during the birthing process), pneumococcus (the most common cause in the elderly), meningococcus (the most common type in college students since it can be transmitted from patient to patient, often with someone being a carrier and not developing symptoms), Haemophilus influenza (despite the name this is not the cause of the flu, it is a bacteria that was named because it was first isolated during an influenza outbreak) and others. Acute bacterial meningitis can progress rapidly, with the potential for severe complications including hearing loss, brain damage (including learning disabilities, memory loss, other), seizures, shock and even death. Therefore, acute bacterial meningitis is considered a medical emergency and antibiotic treatment is begun as soon as it is suspected, and steroid medications to minimize inflammation are also usually administered.

Viral meningitis usually has a slower onset, typically worsening over days. Most cases in the U.S. are due to enteroviruses, although many viruses (including West Nile virus and many others) can cause it. Most cases of viral meningitis resolve without treatment, although in some patients (for example those with immune suppression) or for some viral causes, anti-viral medications exist and are beneficial.

Certain infectious organisms grow slowly (such as fungi, the bacteria tuberculosis and others) and can cause a more chronic form of meningitis, with symptoms progressing over weeks. These types of meningitis are much less common in the U.S., and occur most often in patients with immune system compromise. The specific treatment required depends on the causative infection.

Meningitis from other causes, like toxic reactions to chemicals/medications or autoimmune diseases, are usually suspected based on the patient’s history of exposure or from having a history of, or symptoms of, the autoimmune disease. The treatments for these types of meningitis are aimed at the underlying cause (so stopping the exposure to the chemical, or treating the underlying autoimmune disorder).

As noted above, acute bacterial meningitis has the highest complications rate. Many cases can be prevented or minimized with vaccinations and with appropriate prenatal care (to minimize the likelihood of a newborn acquiring the infection during the birthing process). So, talk with your healthcare provider to determine what may be indicated for you to help prevent this serious disease.